1. Field of the Invention
The present invention concerns novel amino acid derivatives, and their production and uses as intermediates for production of a carbapenam or carbapenem, which is being developed as a drug, for example, an antibiotic having a .beta.-lactam structure.
2. Discussion of the Background
It is known that carbapenem can be produced by bacteria (Kahan et al, J. Antibiotics 32, 1 (1979)), but it is an unstable compound, and in bacterial production the yield is low.
Synthetic methods for its production have been proposed, using as starting materials for example L-aspartic acid (T. N. Saltsmann et al, J. Amer. Chem. Soc., 102, 6161 (1980)); penicillin (S. Karady et al, J. Amer. Chem. Soc., 103, 6765 (1981)); L-threonine (M. Shiozaki et al, Tetrahedron Letters, 5202 (1981)); or D-glucose (N. Ikota et al, Chem. Pharm. Bul., 30, 1929 (1982)). However, prior synthetic processes have problems in that they are complex, the yield is low, and it is difficult to obtain a compound possessing several substituent groups because of the cyclization reaction required to form the five membered ring after the .beta.-lactam ring has been formed.